Open-ear headphone

1. A flexible arm that is configured to be located between and physically and electrically connect an acoustic module of an open-ear headphone to a battery housing of the open-ear headphone, the flexible arm comprising: a flexible printed circuit that extends through the entire original resting length of the flexible arm and comprises a conductor that is configured to carry electrical energy between the acoustic module and the battery housing; a first interface structure coupled to one of the acoustic module and the battery housing; at least one link member pivotably coupled to the first interface structure; and a flexible material that encases the at least one link member, at least some of the flexible printed circuit and at least some of the first interface structure.

2. The flexible arm of claim 1, wherein the at least one link member is pivotably coupled to the first interface structure via a pivot pin that passes through respective holes in the at least one link member and the first interface structure.

3. The flexible arm of claim 1, wherein the at least one link member inhibits twist of the flexible arm.

4. The flexible arm of claim 1, wherein the at least one link member comprises a plurality of link members pivotably coupled to each other in series.

5. The flexible arm of claim 4, wherein the plurality of link members are pivotably coupled to each other via pivot pins that pass through respective holes defined by the plurality of link members.

6. The flexible arm of claim 1, wherein the at least one link member at least partially surrounds the flexible printed circuit.

7. The flexible arm of claim 1, further comprising a guide member coupled to the at least one link member, wherein the flexible printed circuit passes through a channel in the guide member, thereby coupling the flexible printed circuit to the at least one link member.

8. The flexible arm of claim 7, wherein the guide member is formed of silicone.

9. The flexible arm of claim 7, wherein the guide member is coupled to the at least one link member via an adhesive.

10. The flexible arm of claim 1, further comprising a second interface structure coupled to the other one of the acoustic module and the battery housing, wherein the at least one link member is pivotably coupled to the second interface structure.

11. The flexible arm of claim 10, wherein the at least one link member comprises a plurality of link members pivotably coupled to each other and arranged in series between the first interface member and the second interface member.

12. The flexible arm of claim 1, wherein the at least one link member comprises a motion limiting feature that limits rotational movement of the link member.

13. The flexible arm of claim 1, wherein the at least one link member is formed of a rigid plastic.

14. The flexible arm of claim 1, wherein the at least one link member is formed of metal.

15. The flexible arm of claim 1 wherein the flexible material is overmolded on the at least one link member, at least some of the flexible printed circuit and at least some of the first interface structure.

16. The flexible arm of claim 1 wherein the flexible material comprises an external layer of the entire flexible arm.

17. The flexible arm of claim 1 wherein the original resting position of the flexible arm lies along a curved axis that defines a simple open curve.

18. The flexible arm of claim 1, wherein the first interface structure comprises one or more centering features to assist within centering the first interface structure within a cavity in the battery housing.

19. The flexible arm of claim 1, wherein the first interface structure comprises one or more guide members that provide a hard stop that butts up against the battery housing to limit inward movement of the first interface structure into a cavity in the battery housing during assembly.

20. The flexible arm of claim 1, wherein the flexible material defines a gasket that provides a seal between the first interface member and the acoustic module.